Active electronic position sensors are used for a wide variety of purposes, for example, for feedback for control loops noting the position of valves or tailgates in motor vehicles. Such valves and tailgates are driven by an electric motor and their position is detected. The combined assemblies form an actuator. A control unit connected via feed lines, for example, a motor electronic control unit (ECU), controls the electric motor, which, for example, operates an actuating element, the change of position of which is detected by a position sensor via a gear. For operating this position sensor, a supply voltage is required.
In the related art, active position sensors for position detection or position regulation of actuators are supplied with electrical energy (generally voltage) via separate feed lines. There are various output signals for transmitting the actuator position. The known analog interface is ratiometrically proportional to the supply voltage. The supply voltage which is generated as a reference in the control unit must therefore also be connected directly to the position sensor. Supply-voltage-independent (non-ratiometric) output signals of position sensors behave differently. Here, the supply voltage does not necessarily have to be supplied from the control unit if the sensor is able to be supplied with energy in a different manner. However, the problem still exists that a supply voltage which is separate from the motor, for example, of 5 V, must be supplied to the position sensors via separate feed lines. This also applies to the newly introduced digital signal transmission of the position, where, for example, a digital serial SENT protocol is used for a point-to-point connection (no bus).
It is obvious that the arrangement of such separate feed lines is complex.
From U.S. Pat. No. 5,389,864, a position sensor is known. For this known sensor, the electrical energy for the operation of the position sensor designed as a potentiometer is drawn via the control lines of the motor terminals.
An actuator system having a corresponding arrangement of the power supply of the position sensor is known from U.S. Pat. No. 6,545,441 B1.
Furthermore, DE 199 46 917 A1 describes a proximity sensor in which the entire functionality of the sensor is combined in one single integrated component (IC), wherein this is merely supplemented by a power supply for use.